(a) Technical Field
The present disclosure relates to a fluorescent probe which is selectively localized in mitochondria of a cell, an intracellular organelle. More particularly, the present disclosure relates to a two-photon fluorescent probe with high sensitivity and selectivity that can visualize the activation of zinc ions present inside the mitochondria by using a two-photon microscope in real time.
(b) Background Art
A change in the intracellular distribution of zinc ions is very important in studying physiological and pathological activities. In particular, zinc ions serve to regulate sensitivity of the central nervous system, the brain and play an important role in synaptic plasticity. For a proper brain function, it is essential to maintain homeostasis of an intracellular concentration of zinc ions. According to a recent study, it has been found that when the intracellular concentration of zinc ions becomes high, the mitochondria in cells absorb the zinc ions to help the cells maintain homeostasis of zinc ions. If the intracellular concentration of zinc ions loses balance, neurological diseases such as Alzheimer's and Parkinson's diseases may be caused.
To understand the biological roles of zinc ions, a variety of one-photon fluorescent probes derived from quinoline (TSQ, Zinquin, and TFLZn) and fluoroscein (FluZn-3, Znpyr, ZnAF, etc.) have been developed. However, most of such one-photon fluorescent probes are not selective to mitochondria and show poor selectivity to zinc ions.
Further, when a one-photon fluorescence probe is used, there is a common problem of using shorter excitation wavelengths (<500 nm). The short excitation wavelength may cause several problems including a shallow penetration depth (<100 μm), photo bleaching and self-fluorescence of cells, that limit the application for tissue imaging. To solve the problems, there has been proposed a two-photon microscope (TPM) employing a two-photon with low excitation energy. The two-photon microscope has several advantages that it requires low energy for excitation, enables to detect zinc ions in intact cells, and allows to observe biological phenomena in deeper tissues.
However, two-photon fluorescent probes that CaO selectively detect zinc ions present inside mitochondria of cells have not yet been developed.
The present inventors have endeavored to develop a fluorescent marker that can selectively detect zinc ions present inside the mitochondria and solve the problem of the conventional one-photon fluorescent probe with a short excitation wavelength, and therefore developed a two-photon fluorescent probe (SZn-Mito) capable of selectively detecting zinc ions present inside the mitochondria.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.